<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

</body>
<script>
  let formdata = new FormData();
  formdata.append();
  formdata.set();
  formdata.get();
  formdata.delete();
</script>

</html>